Weird wifi problem

[Neomotion]

So, this is the situation. My gf has a macbook (white, 13 inch), running OSX 10.6. I have a macbook pro (13 inch, running mavericks).

When she is connected to the wifi network, all is fine. But, as soon as I turn on my macbook and connect, her connection drops and she has to use the second channel. Anybody knows what is going on here? Everything else stays connected (2 cellphones, tablet). Just her macbook drops as soon as I connect.

Thanks in advance!

 

[Gav2k]

So, this is the situation. My gf has a macbook (white, 13 inch), running OSX 10.6. I have a macbook pro (13 inch, running mavericks).

When she is connected to the wifi network, all is fine. But, as soon as I turn on my macbook and connect, her connection drops and she has to use the second channel. Anybody knows what is going on here? Everything else stays connected (2 cellphones, tablet). Just her macbook drops as soon as I connect.

Thanks in advance!

What make is the router?

Reason I ask is some will run g+n at the same time and some will drop g and only run n band for example.

If that's the case you can solve it temporarily by connecting everything to the g band and later by replacing the router with a newer dual band router.

 

[Neomotion]

It's an UPC Horizon Box by Samsung (Type SMT G7400) (http://www.chelloo.com/informatie/upc-digitale-televisie/mediabox/160-samsung-smt-g7400)

It's weird, because it's just the macbook from my gf, everything else keeps connected. And all are on the 2.7 Ghz band. Any ideas?